A data source apparatus, such as a computer, is connected to a remote device, such as a wireless projector, via a transmission channel, such as a wireless network, so that the remote device shows display images of the data source apparatus. Updated regions of the data source apparatus are detected and analyzed. Corresponding compression methods are then selected according to the characteristics of the updated regions. Then, the updated regions are compressed using the selected compression methods, and the compressed data accompanied by meta data indicating the type of the compression methods and coordinate values of the updated regions are then transmitted to the remote device. Then, the remote device updates its display according to the received data.